Pleuronectiformes!
By: Steve Mussmann
and Christine Knight
Where it’s at…
Monophyletic group 11 families
Pleuronectiformes
Bilaterally symmetrical as larvae Eye migrates and asymmetrical as adult Adults lack swim bladder Mostly marine… only a few freshwater species Compressed body Benthic fishes Eat benthic invertebrates and fish
All the families…
11 familiesAchiridae- American SolesAchiropsettidae- Southern FloundersBothidae- Lefteye FloundersCitharidae- CitharidsCynoglossidae- TonguefishesParalichthyidae- Large Tooth FloundersPleuronectidae- Righteye FloundersPsettodidae- PsettodidsSamaridae- Crested FloundersScophthalmidae- TurbotsSoleidae- Soles
Achiridae- American Soles
33 species Eyed-side lower lip
has fleshy rim Occur in fresh,
brackish, and marine habitats
Achiropsettidae- Southern Flounders 6 species Only marine
habitats Antarctic and
Sub-Antarctic waters
Eyes on left side Pectoral fins tiny
or absent
Bothidae- Lefteye Flounders
162 species Only marine Temperate and
tropical---Atlantic, Indian, and Pacific Oceans
Eyes on left No spines in fins Anus on blind side
Citharidae- Citharids
7 species Only marine Mediterranean,
Indian, and Japan to Australia
Eyes either side Short pelvic fins Anus on eyed
side
Cynoglossidae- Tonguefishes 140 species Fresh, brackish, and
marine habitats Tropical and sub-
tropical Eyes small and on
left side Asymmetrical mouth No pectoral fins Commercially
important
Paralichthyidae- Large-tooth Flounders 116 species Fresh, brackish,
and marine habitats Atlantic, Indian, and
Pacific Oceans Eyes on left side No spines in pelvic
and pectoral fins
Pleuronectidae- Righteye Flounders 102 species Fresh, brackish and
marine habitats---mostly marine
Arctic, Atlantic, Indian, and Pacific oceans
Eyes on right side Camouflage Fins have no spines Commercially
important
http://www.youtube.com/watch?v=ty9f5_pxMas
Psettodidae- Psettodids
3 species Marine only Most primitive
Few vertebrae Swim upright
Eyes on either side
Samaridae- Crested Flounders 21 species Marine only Indo-pacific---
tropical and sub-tropical waters
Deep waters Postcleithrum
absent
Scophthalmidae- Turbots
9 species Brackish and marine
waters North Atlantic, Baltic,
Mediterranean, Black seas
Eyes on left side Large mouth---
prominent jaw
Soleidae- Soles
163 species Fresh, brackish, and
marine habitats Europe to Australia
and Japan Eyes on right side No fin spines Commercially
important
Evolution of Asymmetry
Born with eyes on both sides of head
Gradually migrates so eyes on same side of head
Adults are asymmetrical
http://www.youtube.com/watch?v=bldN-lbyqsE
Matt Friedman 2008
Evolution of asymmetry gradual or in one large jump?
Discovered transitional fossil that has asymmetrical skull eyes on both sides of the head!
Find the Flounder?!
Chromatophore Pigment
containing Light reflecting
http://www.youtube.com/watch?v=GAZSg2tqe7k
Experiment!
Winter Flounder
Conservation… IUCN lists Atlantic Halibut as
endangered and the Yellowtail Flounder as vulnerable
Overfishing Late age of sexual maturity Looking for alternative
species to fish
Review Questions!
Name three traits shared by the Pleuronectiformes. What is unique about the Southern Flounders? In what family is camouflage most common? What are the advantages of camouflage for
Pleuronectiformes? Make an argument for the gradual evolution of
asymmetry in Pleuronectiformes. Describe the development of a flatfish. What are some reasons for the endangered status
of the Atlantic Halibut?